Heretofore, there has been known a method of producing olefins using a metallocene compound and methylaluminoxane as a catalyst in a homogeneous system. For example, Japanese Patent Application Laid-open No. 19309/1983 discloses a method of producing ethylene homopolymers and ethylene/C.sub.3 -C.sub.12 .alpha.-olefin copolymers using biscyclopentadienyl zirconium dichloride and a linear or cyclic methylaluminoxane as a catalyst. Japanese Patent Application Laid-open No. 130314/1986 discloses a method of producing stereoregular polypropylenes using a catalyst comprising a zirconium compound containing as a ligand a compound having two indenyl groups intervened with an ethylene group and aluminoxane. Also, Japanese Patent Application Laid-open No. 41303/1990 discloses a method of producing poly-.alpha.-olefins having a good syndiotacticity.
There have also been proposed catalyst composition systems that use no aluminoxane cocatalyst. Taube et al. performed polymerization of ethylene using a metallocene represented by Cp.sub.2 TiMe(THF)!.sup.- BPh.sub.4 !.sup.+ (Cp: a cyclopentadienyl group, Me: a methyl group, THF: a tetrahydrofuranyl group, Ph: a phenyl group) (J. Organometall. Chem., 347, C9 (1988)). In J. Am. Chem. Soc., 109, 4111 (1987), Jordan et al. reported that a zirconium complex represented by Cp.sub.2 ZrR(L)!.sup.- (Cp: a cyclopentadienyl group, R: a methyl group or a benzyl group, L: a Lewis base) functions as a catalyst for polymerization of ethylene. Japanese Patent Application Laid-open Nos. 501950/1989 and 502036/1989 disclose methods of polymerizing olefins using catalysts comprising a cyclopentadienyl metal compound and an ionic compound which can stabilize the cyclopentadienyl metal cations. Zambelli et al. reported that use of a catalyst which comprises a zirconium compound having a cyclopentadiene derivative as a ligand, trimethylaluminum and fluorodimethylaluminum enables production of isotactic polypropylenes (macromolecules, 22, 2186 (1989)).
However, use of the above-described catalysts, when used in slurry system processes or gaseous system processes, caused problems since the polymer is produced in the form of fine powder having a low bulk density and, hence, it is difficult to handle it and the polymer produced attaches to an inner wall of the reactor.
In order to solve these problems, various proposals have been made to have the catalysts carried on solid carriers.
For example, Japanese Patent Application Laid-open Nos. 108610/1986, 296008/1986, 280703/1988, 22804/1988, 51405/1988, 51407/1988, 55403/1988, 61010/1988, 248803/1988, 100808/1992, 74412/1991, 709/1991 and 7306/1992 disclose methods of producing olefins using solid catalysts comprising inorganic metal oxides such as silica, alumina, silica-alumina and the like having carried thereon metallocene compounds and methylaluminoxane, respectively.
Japanese Patent Application Laid-open Nos. 6003/1989, 6004/1989, 6005/1989, 11104/1989 and 11105/1989 disclose methods in which catalysts are used that comprise a metallocene compound and aluminoxane carried on an organometallic magnesium compound.
Also, Japanese Patent Application Laid-open Nos. 260903/1988, 31403/1992 and 74411/1991 disclose polymerization methods in which catalysts are used that comprise a metallocene compound and aluminoxane carried on polymer such as polyethylene, polystyrene, respectively.
Japanese Patent Application Laid-open Nos. 276805/1986 and 74415/1991 disclose polymerization methods using a metal oxide and a metallocene compound having carried thereon only methylaluminoxane.
Further, Japanese Patent Application Laid-open Nos. 259004/1989, 259005/1989, 56928/1994 and 56929/1994 disclose methods in which catalysts are used that comprise a metallocene compound having a special ligand, carried on a porous metal oxide carrier, such as silica. On the other hand, Japanese Patent Application Laid-open No. 234405/1992 discloses a method of solidifying a catalyst using a cyclopentadienyl group bonded to a poly(halogenated methylstyrene) to form a complex with the catalyst.
Studies have been made in order to obtain solidified catalysts for catalyst systems using no aluminoxane cocatalyst. For example, Japanese Patent Application Laid-open No. 234709/1991, 247128/1993, 239138/1993, 148316/1993, 155926/1993 and 502906/1993 disclose methods in which catalysts are used that comprise a cation type metallocene compound reacted with a non-coordinating boron compound carried on an inorganic metal compound such as silica. However, in these carrying methods, the boron compound is not bonded to the carrier so that upon polymerization, activated species come off from the surface of the carrier, causing the resulting resin to attach to the reactor.
Further, Japanese Patent Application Laid-open No. 501573/1995 (WO 93/11172) discloses a method involving use of an ion-activated transient metal catalyst composition useful for the polymerization of olefins, the composition comprising a core portion and a polyanionic transient metal catalyst component, i.e., a polyanion portion comprising a plurality of metal- or metalloid atom-containing non-coordinating anionic group chemically bonded to the core portion as a side chain. Here, the core portion is comprised by (1) an oligomer of a salt of a polymerizable anionic portion containing a metalloid atom and an organic cation prepared in the presence of a metallocene, (2) cross-linked particles of a polymer such as a styrene based polymer, or (3) inorganic particles such as those of glass, silica, metal, etc. In the above-described publication, there are described examples which used the former two ((1), (2)) as the core and confirmed their effect as a polymerization catalyst. However, when the present inventors tested the examples, the method was insufficient in either one of the activity of olefin polymerization, powder characteristics of the resulting polyolefins, and attachment of the polymers to the reactor.
Therefore, an object of this invention is to provide a carrier-supported olefin polymerization catalyst which is excellent in the activity of catalyst and has solved the problem involved in the conventional methods that the resulting polymer attaches to the wall of the reactor and to provide an ionic compound for use therein.